WO 2002/096501 A2 discloses an ultrasound medical system comprising an ultrasound transducer assembly insertable into a patient, wherein the ultrasound transducer assembly has a longitudinal axis and a plurality P of ultrasound transducers. Each ultrasound transducer has an ultrasound emission surface oriented at an angle of substantially 360/P degrees apart from the ultrasound emission surface of an adjacent ultrasound transducer when viewed in a cross section of the ultrasound transducer assembly taken by a cutting plane which is perpendicular to the longitudinal axis.
US 2004/0242999 A1 discloses an apparatus for delivering acoustic energy to a target site adjacent a body passage. The apparatus comprises a first member with a proximal end, a distal end having a size and shape for insertion into the body passage, and a first transducer carried on the distal end. The apparatus further comprises a second member with a proximal end, a distal end having a size and shape for insertion into the body passage, and a second transducer carried on the distal end. The first and second transducers are detachably coupled to each other to at least partially form a transducer array for delivering acoustic energy to a target site adjacent the body passage.
US 2014/0330124 A1 discloses a system for providing ultrasound, wherein the system comprises a drive shaft having a proximal end and a distal end, a motor positioned at or near the proximal end of the drive shaft and a pair of jaws mounted on or near the distal end of the drive shaft. The system further comprises ultrasound transducers configured to generate thermal or cavitational lesions with ultrasound, wherein each transducer is mounted to one of the jaws.
US 2007/0239011 A1 discloses an apparatus for delivering high intensity focused ultrasound (HIFU) energy to a treatment site internal to a patient's body. The apparatus comprises an elongate probe having a proximal end and a distal end, wherein the proximal end has a section adapted for positioning the distal end of the probe at a desired location within the patient's body. The distal end of the probe has a HIFU therapy transducer coupled thereto, wherein the HIFU therapy transducer comprises a plurality of leaves, each leaf having a proximal end, a distal end, and a deployment mechanism, wherein the proximal end of each leaf is coupled to the distal end of the probe. Each leaf further has a front surface adapted to direct HIFU energy to the treatment site when the probe is inserted in the patient's body and the deployment mechanism is activated. The deployment mechanism is configured to deploy the leaves by directing the distal end of the leaves in a radially outward direction, wherein the leaves thus deployed collectively provide a bowl-shaped HIFU therapy transducer having an outer edge with a diameter that is larger than the diameter of the probe and an aperture of a size sufficient to direct therapeutic HIFU energy to the treatment site. In order to facilitate insertion of the probe in the patient's body, the leaves are configured to collapse when the deployment mechanism is not activated, wherein the collapsed leaves occupy a space having a diameter smaller than the diameter of the outer edge of the HIFU therapy transducer.
US 2014/0081301 A1 discloses an intravascular nerve modulation system comprising an elongate shaft having a proximal end region and a distal end region and an array of ultrasound ablation transducers disposed at the distal end region. Each of the ablation transducers in the array is configured to emit acoustic energy directed towards and intersecting at a first focal region.
WO 2004/108214 A1 discloses an ultrasound probe comprising a probe body and a transducer means for generating a focused ultrasound field, wherein the intensity maximum of which is located in an object for heating the same. The transducer means has a central opening formed by one or more holes for reducing the effect of unwanted peaks in the near ultrasound field.
For ablating a tumor in the prostate it is known to use a transrectal HIFU ablation device. Using the transrectal HIFU ablation device for ablating a tumor in the prostate can lead to unwanted side effects like adversely affecting the urethra, the nerves or the rectum. The side effects can lead to incontinence and erectile dysfunction.